"Build a penal colony"
I don't want to spend a dime on them. The trouble with the Aleutians is that dropping someone off there with the clothes on his back would be a death sentence (I favor killing them myself, but I am assuming the need for a penal colony has arisen because my fellow citizens disagree).
We need a tropical location which can be secured from egress, but I would not invest anything or place any physical objects there.
Drop 'em off naked (or with a prison jumpsuit, I don't care), and let them work it out with each other.
Provision of any sort is morally repugnant to me.
Tropical location? Fine. The hotter the better.